Research areas

Synchrotron radiation based spectroscopy, Xray photoelectron spectroscopy (XPS), atmospheric and environmental nanoparticles, surface chemistry, multiphase interactions, organic surfactants, hygroscopic properties, cloud microphysics, air pollution, climate change.

 

Research methods

In ATMOS group we work to understand the importance of aerosols for various processes at the heart of atmospheric chemistry and global climate. We integrate a wide range of levels of complexity, from molecular characterization and interactions, to single aerosol particles and global responses to aerosol driven processes. For example, we study the chemical properties of a single molecular layer on the aerosol surfaces, how surface chemistry affects single-particle processes like the formation of a cloud droplet, and the global climate effects of clouds in the atmosphere.

We use complementary experimental, theoretical, and computational approaches at each stage. At the heart of our experimental research lies molecular level characterization of atmospheric nano-particles and surfaces using synchrotron-radiation based spectroscopic techniques. Most synchrotron experiments are done at the new MAX IV facility in Lund, Sweden, which is now the world’s brightest synchrotron light source. This unique brightness gives us new possibilities to study properties of the aerosols and their surfaces which we have previously not been able to. For example, we can now get detailed chemical information about the molecules immediately on the surfaces of submicron water droplets.

As part of the Nano and Molecular Systems Research Unit at Oulu University ATMOS collaborates heavily with other research groups on developing new applications of synchrotron radiation, as well as specific instrumentation needed for our research. All Finnish national participation in MAX IV is coordinated from NANOMO. Our Research Unit is a strong driver in the development of experimental systems for synchrotron based research. Currently, NANOMO is in charge of commissioning of the binational Finnish-Estonian Beamline for Materials Science (FinEstBeaMS) that will form a central part of ATMOS’ work from 2017.


The new MAX IV ring seen from the air.


A view along the storage ring inside MAX IV.

 

Two different representations of organic molecules at the water surface.
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The knowledge we gain about aerosols and their surfaces is integrated with global scale atmospheric processes through experimental characterization and thermodynamic modelling of aerosol effects. We use environmental chambers of different sizes to simulate the atmosphere and clouds under controlled conditions. We collaborate with universities abroad, especially Lund University (Aerosol physics) and University of Copenhagen (Copenhagen Chemistry Atmospheric Research) to use their chambers with different experimental configurations.


One of the reactor chambers for simulating atmospheric chemistry.

 

In ATMOS, we have developed several models to simulate multiphase interactions in mixed aerosols. For example, we study the partitioning or surface active organic components in aqueous aerosols and cloud droplets, and surface interactions with vapor-phase organics and aqueous solubility. We also use state of the art online models like the extended AIM model and AIOMFAC.

Ultimately, the impacts of the aerosol processes we study are tested on a global scale using some of the most comprehensive atmospheric chemistry and climate models in the world. Together with Oulu University, we recently joined the EC-Earth Earth Systems Modelling (ESM) consortium. We also work together with developers at the Finnish Meteorological Institute (FMI) using the climate model ECHAM climate model for predictions.


Modeling the distribution of organic components between vapor-phase and aerosol, using Donahue’s Volatility Basis Set (VBS) representation.
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Modeling the global distribution of cloud droplets, and the effect of surface active organics on 5-year average predicted cloud droplet numbers (from DOI: 10.1029/2011GL050467).
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